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Involvement of ezrin/moesin in de novo actin assembly on phagosomal membranes
Author(s) -
Defacque Hélène,
Egeberg Morten,
Habermann Anja,
Diakonova Maria,
Roy Christian,
Mangeat Paul,
Voelter Wolfgang,
Marriott Gerard,
Pfannstiel Jens,
Faulstich Heinz,
Griffiths Gareth
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.2.199
Subject(s) - humanities , chemistry , art
The current study focuses on the molecular mechanisms responsible for actin assembly on a defined membrane surface: the phagosome. Mature phagosomes were surrounded by filamentous actin in vivo in two different cell types. Fluorescence microscopy was used to study in vitro actin nucleation/polymerization (assembly) on the surface of phagosomes isolated from J774 mouse macrophages. In order to prevent non‐specific actin polymerization during the assay, fluorescent G‐actin was mixed with thymosin β4. The cytoplasmic side of phagosomes induced de novo assembly and barbed end growth of actin filaments. This activity varied cyclically with the maturation state of phagosomes, both in vivo and in vitro . Peripheral membrane proteins are crucial components of this actin assembly machinery, and we demonstrate a role for ezrin and/or moesin in this process. We propose that this actin assembly process facilitates phagosome/endosome aggregation prior to membrane fusion.